Vehicle seat suspension with omni directional isolator

ABSTRACT

The present invention is directed to a vehicle seat suspension apparatus that is mechanically simple, inexpensive, occupies little space, and operates effectively with force inputs from any horizontal direction. The invention comprises a base, an isolator, and a plurality of links connected to both the base and isolator so that the isolator is suspended from the base and can move or swing horizontally in all directions relative to the base. The isolator has an upper plate with two flanges that depend from the plate. The base is positioned directly below the upper plate and between the two flanges. The links are connected to the base and the flanges of the isolator by means of ball and socket connectors that permit the isolator to move in all horizontal directions relative to the base. A travel limit system is used to permit adjustment in the travel of the isolator relative to the base.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/873,535 filed Jun. 22, 2004, now U.S. Pat. No. 7,044,553.

BACKGROUND OF THE INVENTION

The present invention relates generally to vehicle seat suspension. Moreparticularly, the invention relates to a vehicle seat suspension whichincorporates a new and unique isolation system for reducing thetransmission of horizontally directed forces to the seat occupant.

For many years, it has been common practice to provide vehicle seatswith some form of “isolation” system. So called “fore and aft” isolatorshave been employed to reduce the undesirable effects of forces inputtedto the seat from the front or back. So too, “lateral” isolators havebeen used for the same purpose with respect to forces input from thesides of the vehicle. Oftentimes, both fore/aft and lateral isolatorsare used together. The combined systems, however, are less thansatisfactory. First they are relatively complex mechanically and aretherefore expensive both to manufacture and install. Second, with spaceconstraints becoming increasingly severe, these combined systems tend topresent too high a profile. Lastly, they tend to react along the foreand aft or lateral axes and therefore do not react as effectively toangular inputs. It would be desirable therefore to provide a truly omnidirectional isolator that is simple in construction, inexpensive tomanufacture, effective in attenuating forces input from all directions,and occupies a relatively small space envelope.

SUMMARY OF THE INVENTION

The present invention is directed to a vehicle seat suspension apparatusthat achieves the aforementioned goals. It is relatively small,mechanically simple, inexpensive, and operates effectively with forceinputs from any horizontal direction. The invention comprises a base, anisolator, and a plurality of links connected to both the base andisolator so that the isolator is suspended from the base and can move orswing horizontally in all directions relative to the base.

In the illustrated preferred embodiment the isolator is constructed withan upper plate having two flanges that depend from the plate. The baseis positioned directly below the upper plate and between the twoflanges. The links are connected to the base and the flanges of theisolator by means of ball and socket connectors that permit the isolatorto move in all horizontal directions relative to the base.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features which are characteristic of the present invention areset forth in the appended claims. However, the invention's preferredembodiments, together with further objects and attendant advantages,will be best understood by reference to the following detaileddescription taken in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of one preferred embodiment of the presentinvention;

FIG. 2 is another perspective view of the preferred embodimentillustrated in FIG. 1 with the isolator plate removed to show details ofconstruction;

FIG. 3 is a side view of the same preferred embodiment shown in FIG. 1;

FIG. 4 is an enlarged cross-section view of certain components circledin FIG. 3;

FIGS. 5 and 6 are end views of the embodiment of FIG. 1, showingrespectively centered and displaced positions of the isolator;

FIG. 7 is an enlarged perspective view, in partial cross-section,illustrating one preferred link mechanism useful in the practice of thepresent invention.

FIG. 8 is a perspective view of another preferred embodiment of theinventions showing an alternative travel limit system; and

FIGS. 9 and 10 are still further perspective views of the embodimentshown in FIG. 8 with the travel limit system retracted for maximumisolator travel or extended for minimum isolator travel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings, a vehicle seat suspension apparatus isillustrated in one preferred form and designated generally as 10. Thesuspension apparatus 10 includes, as basic components, a base 12, anisolator 14 and a plurality of links 16 which are used to suspend theisolator from the base.

The base 12 may take many forms well known to those skilled in the art.In the illustrated embodiment the base has a lower platform 20 and anupper platform 22 mounted to permit vertical movement of the twoplatforms relative to one another. The mechanism that provides thisvertical movement functionality is shown to be a conventional scissorslinkage 24, although many other designs may be employed. As thefollowing description will make clear, the base may comprise anysuitable structure that will accommodate the links 16 and support theisolator suspended from it. To that end, the upper platform includes aplurality of fixtures 26 that support the connector to which the links16 are assembled.

The isolator 14 comprises an upper plate 28, to which the seat ismounted in any conventional manner, and a pair of flanges 30 dependingfrom opposing sides of plate 28. Fixtures 32 are located adjacent thebottom edges of the flanges and serve to support the connector to whichthe links 16 are assembled. The upper plate 28 and flanges 30 aredimensioned so that the base platform 22 may be positioned under theplate and between the flanges, as shown. The flanges 30 also haveapertures or cutouts 34 located at the point where the links areconnected to the flanges. These apertures 34 allow movement of theisolator relative to the base without interference between the flangesand the links. Those of skill in the art will appreciate that the amountof isolator movement or travel that can be achieved is a function of theheight of the flanges, and therefore the length of the links, togetherwith the amount of separation between the edges of the upper platform 22and the downwardly extending flanges 30. Longer links and greaterseparation will allow greater isolator travel.

The links 16 are each made up of an intermediate segment whichterminates at each end in a connector 40. As illustrated, the connectors40 have a socket configuration designed to cooperate with the ballconnectors 42 mounted to the fixtures 26 and 32. Together, theconnectors 40 and 42 comprise a connection that permits the links tomove through 360 degrees around the links' vertical orientation. Thus,the isolator 14 is able to move in any horizontal direction relative tobase 12.

One preferred embodiment of the invention also makes use of an isolatortravel limit system comprising first and second stop members associatedwith the base and isolator. As illustrated, a stop post 46 extends fromthe upper platform 22 and through stop aperture 48 located in theisolator upper plate 28. The stop post may be fitted with a conicalbumper 50, preferably made of a suitable elastomer. The aperture 48 mayalso include and elastomeric bumper 52. As a result, the travel ofisolator 14 is limited by the engagement of the two stop members. Thoseof skill in the art will appreciate that the positions of the post 46and aperture 48 may be reversed so that the post extends down from theisolator and through the aperture located on the base.

In accordance with another preferred embodiment of the invention, a lockout system may also be employed. Again, with reference to theillustrated embodiment one or more lock pins 56 extend upwardly from theupper platform 22 and through appropriately situated lock apertures 58in the isolator. One or more latch plates 60 are mounted to a lock outactuation lever 62 which permits movement of the latch plates to engageor disengage the lock pins 56. When engages the isolator 14 is locked infixed position relative to the base 12.

There are important advantages associated with the present invention.One is that because of the gravitationally controlled, self centeringcharacteristics of this suspended isolator design, there is no need forcentering springs as are commonly used with most prior art isolatorsystems. Another advantage has to do with the specific path of travel ofthe isolator. As the isolator moves off its center position it not onlytravels horizontally, but also along an upwardly curving path. Thiscreates an increasing resistance to further movement, or the equivalentof an “increasing spring rate” resistance, which is a desirableattribute in seat isolation systems. Still another advantage of thepresent invention is that there is very little resistance to movement ofthe isolator at or near its center point. This allows the system to bemore effective in attenuating high frequency and low magnitude inputs ascompared to conventional isolators using spring and shock absorberarrangements. Finally, the isolator system of the present invention hasa much lower profile than conventional isolator systems.

Another preferred embodiment of the invention is illustrated in FIGS.8-10, showing an alternative travel limit system comprising first andsecond stop members 70 and 72, respectively. In this embodiment, thefirst stop member 70 comprises flanges 74 positioned on the perimeter ofan opening in the upper plate 28 of isolator 14. The second stop member72 comprises bumpers 76 mounted to the outer ends of bumper stems 78.The stems 78, in turn, are mounted to upper platform 22 (or riser 79situated on platform 22) by u-shaped brackets 80, thereby allowing thebumpers 76 to move radially relative to the center point of the platform22. In this embodiment, the travel limit system employs an adjustmentmechanism including a bumper adjustment knob 82, a threaded adjustmentshaft 84, and a cam wheel 86. A linkage, including a cam wheel centerpivot 88, a cam lever 90 and threaded drive pin 92, is used to connectthe threaded shaft 84 to the cam wheel 86. Cam wheel 86 also includes aseries of cam surfaces 94, each of which engages the inside end of oneof the bumper stems 78. A spring 96, or other biasing means, is used tourge each of the stems 78 inwardly to engage its associated cam surface94.

To adjust the travel limit of the isolator in accordance with thisembodiment, the operator simply turns knob 82, thereby rotating shaft84. This results in linear motion of drive pin 92 and rotation of lever90, so that cam wheel pivot 88 and the cam wheel 86 will also rotateeither clockwise or counterclockwise. A clockwise rotation of the camwheel 86 results in positioning of the respective cam surfaces 94 attheir outer extent, thereby radially extending the bumper stems andbumpers. This reduces or eliminates any travel in isolator 14. Rotationof the cam wheel in the counterclockwise direction will result inretraction of the cam surface 94, so that the bumpers 76 also will beretracted. This allows maximum travel of the isolator 14. As withearlier embodiments, each of the first and second stop members may beassociated with either of the isolator and the upper platform.

It will be appreciated by those skilled in the art that various changesand modifications can be made to the illustrated embodiments withoutdeparting from the spirit of the present invention. All suchmodifications and changes are intended to be covered by the appendedclaims.

1. A vehicle seat suspension apparatus comprising: a base; an isolatorpositioned above the base; a plurality of links for suspending theisolator from the base, the links being connected to the base andisolator in a manner permitting the isolator to move horizontally in alldirections relative to the base; and a travel limit system operativelyconnected to both the base and the isolator including a plurality ofstops and a plurality of elastomeric bumpers, each stop being associatedwith one of said bumpers, and an adjustment mechanism to permitvariation of the amount of travel of the isolator relative to the base.2. The vehicle seat suspension apparatus of claim 1 wherein theadjustment mechanism includes a linkage to vary the spacing between thebumpers and the stops.
 3. The vehicle suspension apparatus of claim 2further including a cam wheel having a plurality of cam surfaces; thecam surfaces acting on the bumpers to locate the bumpers relative to thestops.